Mixers, particularly mortar mixer



July 31, 1956 P. AUGUST 2, 75

MIXERS, PARTICULARLY MORTAR MIXER Filed 001.. 21. 1953 2 Sheets-Sheet l INVENTOR. PABL A ueusT' July 31, 1956 P. AUGUST MIXERS, PARTICULARLY MORTAR MIXER 2 Sheets-Sheet 2 Filed Oct. 21, 1953 INVENTOR. VAmo Aueus'r' United States Patent 2,756,975 Patented July 31, 1956 fitice MIXERS, PARTICULARLY MORTAR MIXER Pablo August, Bernal, Argentina Application October 21, 1953, Serial No. 387,451

4 Claims. (Cl. 259-161) My present invention relates to certain new and useful improvements in mixing machines and more particularly refers to an improved concrete or mortar mixer of the type comprising an inclined casing for receiving the mixture components and worm means in this casing for conveying and mixing the different materials such as sand, gravel and cement.

The known concrete mixers are in general relatively heavy machines which are not only expensive in their construction and operation, but are also disadvantageous insofar as a perfect cleaning of the same is rather difficult with the result that the elaborated concrete sets on the bottom and walls of the mixing receptacle as well as on the moving parts of the mixer and renders the machine inoperative. Another disadvantage of the known mixers resides in that both the supply means of the different mixture components and the proper mixing means do not satisfactorily operate and that in View hereof the mixer is unable to maintain the proportion of ingredients constant and to ensure a good mixing effect.

The present invention aims at eliminating the aforementioned disadvantages and its main object is to provide an improved mixer, characterized by that it comprises an inclined composite casing composed of a fixed casing portion for receiving and conveying the solid mixture components and of a rotary casing portion for mixing said components and for discharging therefrom the mixture, and a stepped worm means extending longitudinally through said inclined composite casing and comprising worm portions of stepwise increased diameter for effecting the conveying and mixing operations in the fixed and rotary casing portions, respectively, said composite casing including an attachment containing a control device for regulating the supply of at least one of the mixture components and the rotary casing portion being provided with transmission means for operating the same from a driving motor.

The arrangement of the composite casing and of the stepped worms of my improved mixer as set forth in the preceding paragraph is particularly advantageous insofar as the supply of the mixture components to the rotary casing portion or mixing drum is uninterrupted, the proportion of ingredients is maintained constant and the mixing operation is uniform and eificient so that in spite of a relatively reduced diameter of the composite casing referred to the output of the mixer is relatively high.

According to one feature of the invention, the fixed casing portion of my improved mixer is provided with a cylindrical extension projecting axially into the rotary casing portion thereof with the advantageous result that the introduction of the mixture components into said rotary casing portion or mixing drum takes place within the latter at a point onor near the axis thereof.

In accordance with another feature of my invention, the improved mixer as hereinbefore set forth includes control means for regulating the supply of at least one of the mixture components e. g. the cement of a concrete mixture, which is arranged between the said cylindrical extension of the fixed casing portion and a suitable hopper for said one mixture component and comprises the combination of a usual toothed roller with a slide valve, this combination being characterized by that slidable plug bodies are provided between the teeth of said roller and are secured to an annular member surrounding said roller, in such an arrangement that said plug bodies by means of one or a pair of rods or the like may be adjusted so as to be in alignment with the inner end of said slide valve, with the advantageous result that the mixture component supplied by said hopper is prevented from entering the spaces between the teeth of the roller situated below said valve and from thereby rendering inexact the regulation of the supply of the said mixture component.

An important feature of my present invention consists in that the rotary casing portion or mixing drum of the improved mixer comprises a composite shell formed by two or more removable shell portions in such an arrangement that their removal and cleaning as well as the cleaning of the inner parts of the mixing drum may be readily effected.

The rotary casing portion or mixing drum of the machine according to my invention comprises a skeleton formed by two or more rings and connecting rods secured to said rings, and these connecting rods are provided with outer projections for securing thereto the different portions of the composite drum shell in an easily removable manner. In view of the relatively small diameter of the mixing drum it may be sufficient to form the drum shell of two semi-cylindrical portions; if desired, each of these portions may be transversely subdivided into two halves. The shell portions are conveniently formed with longitudinal flanges provided with small studs and perforations, respectively, in such an arrangement that the studs of one shell portion pass through the perforations of the adjacent shell portion, and the adjacent flanges of two shell portions may be efficiently held in place by means of simple clamp devices. If desired, two opposite connecting rods of the drum skeleton may have a T-shaped cross section and the outwardly projecting webs may be provided with'perforations for receiving the afore-mentioned studs of the shell portions. Further, the other two connecting rods of the drum skeleton may be provided with outwardly projecting studs for engaging corresponding perforations provided along the center line of the shell portions and thereby assisting in fixing the drum shell.

According to an additional feature of the invention the rotary casing portion or mixing drum comprises at least at both ends thereof annular members surrounding the drum and providing circular rails for pairs of loose rollers mounted on an inclined supporting frame, whereby said drum is rotatively disposed on said frame. The drum for being rotated may be provided with a toothed rim which, if desired, may form part of one of the said annular members and which is operated from a driving motor by means of a chain, pinion or the like.

With these objects and advantageous features in view, my present invention comprises the arrangement, combination and construction of parts as will be hereinafter fully described with particular reference to the accompanying 'idrawings whereon a preferred embodiment of the invention has been illustrated by way of example only and whereon:

I Figure 1 is a schematic partly sectional side elevation of the improved mixer according to my invention;

Figures 2 and 3 are cross sectional views taken along the lines 2-2 and 33 of Figure 1, respectively;

Figure 4 is an end view of the mixing drum;

Figures 5 and 6 show in a cross section and longi- V tudinal section, respectively, the'control means for regu- .inclined supporting frame 1.

3 lating the supply of one of the mixture components; and

Figures 7 and 8 are detail views showing a clamp device for holding together the adjacent flanges of two portions of thecomposite drum shell.

In these figures, likereference numerals refer to like or corresponding parts of the machine.

Referring to the accompanying drawings, the improved mixer according to my present invention comprises an The lower end of this frame rests on the ground, whereas its upper end is provided with a suitable support 2. If desired, the frame 1 may be mounted on the chassis of a vehicle for moving the machine from one place to another.

The lower portion of the frame 1 carries fixedly mounted thereon a trough-like casing 3 provided with a hopper 4 which-directly communicates with the interior of the casing 3 and which is transversally subdivided by an adjustable partition 5 to provide two compartments 6, 7 for e. g. sand and gravel, respectively. Adjacent this hopper 4 there is another one 8 for containing e. g. cement. The cross section of the casing 3 is substantially circular'except at the top thereof Where the side Walls diverge to form the hopper 4.

The lower end of the frame 1 or the front wall of the casing 3 carries a bearing indicated at 9 for rotatively mounting a shaft 10 provided with a stepped worm i. e. a helical blade of different diameter in such an arrangement that the worm of the smallest diameter 11 extends through that portion of the casing 3 situated below the hopper compartment 6, whereas the worm portion 12 of a substantially larger diameter extends through the adjacent casing portion situated below the hopper compartment 7 and through a cylindrical extension 13 which forms part of said casing 3 and which by way of an attachment25 containing the control means for regulating the supply of one of the mixture components (see Figures 5 and 6) is communicated with the hopper 8.

The cylindrical extension 13 of the fixed casing 3 projects axially into a rotary casing or mixing drum 14 which is co-axial with said'fixed casing 3 and together with the latter forms the composite casing of the machine. The mixing drum 14 is rotatively arranged on the inclined frame 1 and for this purpose is provided with annular members 15 having an L-shaped cross section and providing rails for rotatively supporting the drum on pairs of loose rollers 26 (Figure 4) suitably mounted on the frame 1.

The rotary casing or mixing drum 14 comprises a skeleton formed by a number of rings (not shown) and connecting rods 16a, 16b rigidly secured to said rings and adapted to constitute the supports for the shell of the drum 14, while said rings at the same time carry the afore-rnentioned L-shaped annular members 15. The shell of the drum 14, according to this invention, is composed of at least two shell portions 14a, 14b which, however, if desired, may be transversally subdivided into two halves so that the shell is composed of four portions.

For securing these shell portions 14a, 14b in place, one pair of opposite connecting rods 16a is provided with outwardly projecting studs 17 (Figure 3) which extend through corresponding perforations provided along the center line of each shell portion, whereas the second pair of opposite connecting rods 16b are of T-shaped cross section, the webs 18 of which project outwardly between the flanges 13a, 19b (Figure 7) of the shell portions 14a, 1411. For fastening these flanges on the web 18, one of said flanges e. g. 19a is provided with clamp devices 20 (Figures 7 and 8) and with small studs 21. These studs 21 extend through corresponding perforations provided in the web 18 and the flange 19b and the arrangement being such that while the shell portions 14a, 141) are being placed on the drum skeleton, the clamp devices 20 are swung outwards so that they are not in'the way of the studs 21 when being inserted into the perforations of the web 18 and of the flange 1%, but thereafter said clamp devices are swung back to their operative position in which they engage the free protruding end of the studs 21 and thus hold the flanges 19a, 1% together. It will be understood that the web 18 of the connecting rods 16b is not absolutely necessary and that the same may be readily dispensed with in view of that the interconnection of the flanges 19a, 1% by means of the studs 21 and of the clamp devices 20 is quite sufficient for securing the shell portions in place.

For operating the mixing drum 14, one of the annular members 15 may be provided with a toothed rim 22 which is engaged by a pinion or a chain and is operated thereby from a drivingmotor (not shown). If desired, the operation of the drum 14 may also be effected by suitably connecting the driving motor with an extension of the shaft 11 provided the same carries fixedly mounted thereon cross pieces rigidly connected with the connecting rods 16a, 16b. In any case, the arrangement of the drivingmechanism will be such that it simultaneously operates the control means for regulating the supply of at least one of the mixture components, which will be hereinafter described. It will be understood that the toothed rim 22 instead of forming part of one of the annular members 15, may also be arranged around the center portion of the drum 14, and in this case the shell portions 14a, 14b will have to be transversally subdivided'into two halves.

The control means for regulating the supply of the mixture component contained in the hopper 8 comprise a toothed roller --23 fixedly mounted on and operated by its shaft 24 and arranged within a casing 25 which is communicated at the one hand with the cylindrical extension 13 of the fixed casing 3 and at the other hand with the hopper 8, this latter communication being controlled-by a slide valve '27. For avoiding that part of the mixture component, e. g. cement, supplied by said hopper 8 enters the spaces between the teeth of the roller 23 below saidslide valve 27 and renders the regulation of the cement supply inexact, according to my invention, there is provided a device comprising a number of plug'members 28 secured to'a ring member 29 surrounding-the roller 23. These plug members have a cross section corresponding to that of the spaces between the teeth of the roller 23 and are movable along these spaces so that they may be adjusted by means of rods or the like in alignment with the inner end of the slide valve 27, in which position they efficiently prevent the cement=from fillingsaid spaces below said slide valve.

For eifectingthe mixing ofthe materials in the interior of the drum 14, the latter'comprises a composite helical blade which is a' continuation of the blade 12. This blade 12 which extends from the casing 3 through the cylindrical extension 13, at the upper end of thelatter increases its diameter to that of the drum 14 and forms a helical disk 31which provides a connection between the helical blade and a composite helical blade 32, 33 secured to the connecting rods 16a, 16b of the drum skeleton. This composite helical blade comprises blade portions 32 and 33 which are alternatively arranged in direct contact with the inner surface of the drum shell and at certain small distance therefrom as has been clearly shown in Figure 2. These'blade portions are of a breadth of approximately one eighth of the diameter of the drum and cover each an angle of and project radially into the interior of the drum.

The composite helical blade 32, 33 effects a very uniform mixing of the mixture components supplied by the worm 11, 12, '3l at'first in dry condition and thereafter with water or any otherliquid supplied by a perforated pipe '34, and finally discharges the mixture through the open end ofthe drum '14. In the case that the drum 14 is mounted by means of cross pieces on an extension of the shaft 10,- this'extensionmust be'hollow and perforated '5 so that the supply of water may be effected'through said hollow shaft.

As particular features of the mixer according to my invention there are to be particularly noted: the inclined casing composed of a fixed casing portion 3, 13 and of a rotary casing portion or mixing drum 14 arranged coaxially with one another, and the continuous stepped worm composed of the blade portions 11, 12, 31 and 32, 33 of stepwise increased diameter extending throughout the complete composite casing.

After properly adjusting the partition 5, the slide valve 27 and the plug members 28, the operation of the mixer is automatic, the proportion of ingredients is maintained constant and the mixing effect is uniform and productive.

Before the machine is started, the hopper compartment 6 is filled with sand so that the lower end portion of the casing 3 is completely filled, and the hopper 8 is charged with cement while the slide valve 27 is closed. Now the machine is started and the worm 11 starts conveying the sand to the casing portion situated below the hopper compartment 7. In view of the presence of sand in the worm portion 12 the gravel which is now introduced into the hopper compartment 7 cannot damage said worm portion. This worm portion 12 conveys sand and gravel into the cylindrical extension 13 and now the slide valve 27 is opened so that cement is added to the sand and gravel in a predetermined proportion according to the position of said slide valve 27 and of the plug members 28. The three mixture components are submitted in the cylindrical extension 13 to a preliminary mixing operation and by means of the helical disk 31 are continuously delivered into the rotating drum 14, wherein they are thoroughly mixed by the composite helical blade 32, 33 at first in dry condition and thereafter with water supplied by the pipe 34. Practical tests proved that the resulting mixture is homogeneous and that the proportion of ingredients is maintained constant.

Sand, gravel and cement may be continuously charged into the respective hoppers and the operation of the mixer is also continuous. After finishing a days work, the clamping devices 20 are swung outwards, whereupon the shell portions 14a, 14b may be removed and the mixing drum may be easily and efficiently cleaned so that any traces of concrete are prevented from setting on the inner surface of the drum shell as well as on the inner parts of the mixing drum.

It has to be understood that the present invention is not restricted to the embodiment as described and illustrated, but that amendments and modifications as to the arrangement and construction of parts may be made therein, and that such amendments and modifications are to be considered as falling within the scope of the invention as clearly set forth and outlined in the appended claims.

What I claim as new and desire to secure by Letters Patent is:

l. Continuously operating mixer, in particular a con crete mixer, comprising a composite conveying and mixing casing, a frame structure for supporting said casing in an inclined position, a lower casing portion fixedly secured to said frame and provided with hopper and adjustable supply means for charging the mixer with the solid components of the mixture to be prepared, and an upper drumlike casing portion rotatively mounted on said frame in axial alignment with said fixed lower casing portion for so forming said composite conveying and mixing casing; a conveyor screw in said fixed lower casing portion and operatively connected therewith in axial alignment mixing screw means in said drum-like rotary casing portion for conveying and mixing the mixture components and for discharging the finished mixture; a composite shell and a skeleton for carrying said shell forming said rotary casing portion; flange means provided in connection with said skeleton and with the portions of said composite shell for removably securing said shell portion to said skeleton; anda perforatedpipe extending into said rotary casing portion for providing a liquid-supply means.

2. Continuously operating mixer, in particular a concrete mixer, comprising a composite conveying and mixing casing, a frame structure for supporting said casing in an inclined position, a lower casing portion fixedly secured to said frame and provided with hopper and adjustable supply means for charging the mixer with the solid components of the mixture to be prepared, and an upper drumlike casing portion rotatively mounted on said frame in axial alignment with said fixed lower casing portion for so forming said composite conveying and mixing casing; a conveyor screw in said fixed lower casing portion and operatively connected therewith in axial alignment mixing screw means in said drum-like rotary casing portion for conveying and mixing the mixture components and for discharging the finished mixture; a composite shell and a skeleton for carrying said shell forming said rotary casing portion, said skeleton including a number of longitudinal rods and these rods and the portions of the composite shell comprising longitudinal flange member-s provided with studs and perforations in combination with clamp members for interconnecting the shell portions; and a perforated pipe extending into said rotary casing portion for providing a liquid-supply means.

3. Continuously operating mixer, in particular a concrete mixer, comprising a composite conveying and mixing casing, a frame structure for supporting said casing in an inclined position, a lower casing portion fixedly secured to said frame and provided with hopper and adjustable supply means for charging the mixer with the solid components of the mixture to be prepared, and an upper drum-like casing portion rotatively mounted on said frame in axial alignment with said fixed lower casing portion for so forming said composite conveying and mixing casing; a conveyor screw in said fixed lower casing portion operatively connected therewith in axial alignment mixing screw means in said drum-like rotary casing portion for conveying and mixing the mixture components and for discharging the finished mixture, said conveyor screw being composed of a first worm portion having a small diameter and being arranged in the lower end portion of the fixed lower casing portion and of a second worm portion of a larger diameter extending through the upper end portion of said first casing portion and through a tubular extension of the latter, the transition between said two worm portions being gradual and situated below an adjustable partition wall provided in the lower one of said hoppers for regulating the supply of materials to said conveyor screw, and said mixing screw being composed of a third worm portion formed by a helical disk of increasing diameter arranged in the lower end portion of said rotary drum-like portion and of a fourth worm portion formed by a composite helical blade and arranged on the inner surface of said rotary casing portion; a composite shell and a skeleton for carrying said shell forming said rotary casing portion, said skeleton being formed by at least one pair of ring members and a number of longitudinal rods secured to said ring members, these rods and the portions of the composite shell comprising longitudinal flange members provided with studs and perforations in combination with clamp members for interconnecting the shell portions; and a perforated pipe extending into said rotary casing portion for providing a liquid-supply means.

' 4. Continuously operating mixer, in particular a concrete mixer, comprising a composite conveying and mixing casing, a frame structure for supporting said casing in an inclined position, a lower casing portion fixedly secured to said frame and provided with hopper and adjustable supply means for charging the mixer with the solid components of the mixture to be prepared, and upper drum-like casing portion rotatively mounted on said frame in axial alignment with said fixed lower casing portion for so forming said composite conveying and mixing casing; a conveyor screw in said fixed lower casing'portion and operatively connected therewith in axial align- -ment mixing screw means in said drum-like rotary casing and for discharging the finished mixture, said conveyor screw being composed of a first worm portion having a small diameter and being arranged in the lower end portion of the fixed lower casing portion and of a second worm portion of a larger diameter extending through the upper end portion of said fixed casing portion and through a tubular extension of the latter, the transition between said two worm portions being gradual and situated below an adjustable partition wall provided in the lower one of said hoppers for regulating the supply of materials in said conveyor screw, and said mixing screw being composed of a third Worm portion formed by a helical disk of increasing diameter arranged in the lower end portion of said rotary drum-like portion and of a fourth worm portion formed by a composite helical blade and arranged on the inner surface of said rotary casing'portion, said fourth worm portion being composed of narrow blades secured to a skeleton of said rotary casing portion and projecting radially into the interior of the latter, and said blades being arranged alternatively in direct contact with iii the inner surface of a drum shell forming said rotary casing portion and at a small distance from said inner surface; a composite shell and a skeleton for carrying said shell forming said rotary casing portion, said skeleton being-formed by'at leastonepair of ring members and a number of longitudinal rods secured to said ring members, these rods and the portion of the composite shell comprising longitudinal flange members provided with studs and perforations in combination with clamp members for interconnecting the shell portions; and a perforated pipe extending into said rotary casing portion for providing a liquid-supply means.

References Cited in the file of this patent UNITED STATES PATENTS 877,918 Emal Feb. 4, 1908 903,426 Wolter et al Nov. 10, 1908 919,074 Phillips Apr. 20, 1909 1,814,483 Morgan July 14, 1931 2,158,513 Lloyd May 16, 1939 2,608,395 'Aug ust Aug. 26, 1952 FOREIGN PATENTS 435,215 'Great Britain Sept. 17, 1935 

